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JavaScript•Objects, Classes, and Advanced Patterns

JavaScript Object Methods

Flash cards

Review the key moves

1/4

Core idea

What is the main idea behind JavaScript Object Methods?

Lesson checks

Practice each idea before moving on

Short Mimo-style checks built from this lesson's code, terms, and sequence.

1Quick choice

Which statement best captures the main point of this lesson?

2Fill blank

Complete the missing token from the example code.

firstName: "John", lastName: "Doe", age: 50, fullName: ___() {

3Order

Put the learning moves in the order that makes the concept easiest to apply.

Adding a JavaScript Method

Adding a Method to an Object

Accessing Object Methods

What are Object Methods?

Methods are actions that can be performed on objects.

Methods are functions stored as property values .

Example

const
person = {
  firstName: "John", lastName: "Doe", age: 50, fullName: function() {
    return this .firstName + " " + this .lastName;
  }
};

Property	Value
firstName	John
lastName	Doe
age	50
fullName	function() { return this.firstName + " " + this.lastName; }

The this Keyword

In an object method, this refers to the object.

Example 1

const person = {
  firstName: "John", lastName: "Doe", id: 5566, getId: function() {
    return this .id;
  }
};
let number = person.getId();

In the example above, this refers to the person object .

this.id means the id property of the person object .

Example 2

const
person = {
  firstName: "John", lastName: "Doe", age: 50, fullName: function() {
    return this .firstName + " " + this .lastName;
  }
};

In the example above, this refers to the person object .

this.firstName means the firstName property of the person object .

this.lastName means the lastName property of the person object .

Accessing Object Methods

To call an object method, add parentheses () :

Without parentheses you get the function itself.

Syntax

objectName.methodName
()

If you call a method with parentheses , it will execute as a function :

name = person.fullName();

If you call a method without parentheses , it will return the function definition :

name = person.fullName;

Adding a Method to an Object

You can add a method to an object by assigning a function to a property :

Example

// Assign person.name to a function person.name = function () {
return this.firstName + " " + this.lastName;
};

In the example above, person.name is a property with a function assigned to it.

Adding a JavaScript Method

This example uses the JavaScript toUpperCase() method to convert a text to uppercase:

person.name = function () {
 return (this.firstName + " " + this.lastName).toUpperCase();
};

Summary

Methods are functions stored as object properties
Call a method with parentheses: person.fullName()
In methods, this refers to the object
You can add methods to objects by assigning a function to a property

JavaScript Object Methods

Flash cards

Review the key moves

1/4

Core idea

What is the main idea behind JavaScript Object Methods?

Lesson checks

Practice each idea before moving on

Short Mimo-style checks built from this lesson's code, terms, and sequence.

1Quick choice

Which statement best captures the main point of this lesson?

2Fill blank

Complete the missing token from the example code.

firstName: "John", lastName: "Doe", age: 50, fullName: ___() {

3Order

Put the learning moves in the order that makes the concept easiest to apply.

Adding a JavaScript Method

Adding a Method to an Object

Accessing Object Methods

What are Object Methods?

Methods are actions that can be performed on objects.

Methods are functions stored as property values .

Example

const
person = {
  firstName: "John", lastName: "Doe", age: 50, fullName: function() {
    return this .firstName + " " + this .lastName;
  }
};

Property	Value
firstName	John
lastName	Doe
age	50
fullName	function() { return this.firstName + " " + this.lastName; }

The this Keyword

In an object method, this refers to the object.

Example 1

const person = {
  firstName: "John", lastName: "Doe", id: 5566, getId: function() {
    return this .id;
  }
};
let number = person.getId();

In the example above, this refers to the person object .

this.id means the id property of the person object .

Example 2

const
person = {
  firstName: "John", lastName: "Doe", age: 50, fullName: function() {
    return this .firstName + " " + this .lastName;
  }
};

In the example above, this refers to the person object .

this.firstName means the firstName property of the person object .

this.lastName means the lastName property of the person object .

Accessing Object Methods

To call an object method, add parentheses () :

Without parentheses you get the function itself.

Syntax

objectName.methodName
()

If you call a method with parentheses , it will execute as a function :

name = person.fullName();

If you call a method without parentheses , it will return the function definition :

name = person.fullName;

Adding a Method to an Object

You can add a method to an object by assigning a function to a property :

Example

// Assign person.name to a function person.name = function () {
return this.firstName + " " + this.lastName;
};

In the example above, person.name is a property with a function assigned to it.

Adding a JavaScript Method

This example uses the JavaScript toUpperCase() method to convert a text to uppercase:

person.name = function () {
 return (this.firstName + " " + this.lastName).toUpperCase();
};

Summary

Methods are functions stored as object properties
Call a method with parentheses: person.fullName()
In methods, this refers to the object
You can add methods to objects by assigning a function to a property